Aluminum or Stainless Steel?

Wort? This is a winemaking NG!

Still, in either case it's best to use stainless. Aluminum is too reactive for winemaking, and maybe for beer making as well.

BTW, although heating the wort is normal practice in brewing beer, there is no reason to heat the ingredients in winemaking.

Tom S

This is also "a" meadmaking and brewing newsgroup.

Not for brewing.

Does that presume making wine from (presumably sanitary) juice or concentrates? If one is using fresh fruit would pasteurization be called for?

Wineries make wine from fresh fruit and _never_ pasteurize the juice/must.

Tom S

Interesting. I know that in the brewing world, people who brew at home do so with different equipment and in an environment that is often not as clean as a commercial facility may be, so homebrewers often take some extra precautions and/or use somewhat different procedures than do commercial breweries. Are there no such considerations in the winemaking milieu?

No -- I prefer stainless for ease of cleaning, but there's no requirement that your brewpot be shiny clean -- I just hate dirty equipment.

I just noticed this was crossposted to the wine groups. Al is fine for beer. Possibly not for wine, and I don't know about mead.

I agree with Tom - use stainless steel or food-grade plastic - do not use aluminum. I have an aluminum pot and it reacts funny to certain things you cook in it - I would NOT use it for making wine. Darlene

You'll be fine. When you say must, I'm assuming that your talking about mead and other wild wines as grape must doesn't need to be heated. Charlie Papazian has given aluminum pots a blessing saying that even large breweries tend to use copper material and that like copper, aluminum tends to heat more evenly. I do recommend, however, that you get an acid blend, fill your aluminum pot up with water, put in the blend then bring to a boil. It will likely darken the aluminum from oxidation. Don't scrub this off as shiny aluminum is not what you want. You want this protective layer of oxidation. Then you can relax and have a homebrew.

Also, keep in mind that many brewers will freak out if you say you use aluminum or copper, yet they'll boil thier copper wort chillers in their wort to sanitize it for a good 45 minutes including sanitizing it and using it to cool their wort. My advice to you is to disregard them and try it with a five gallon batch, then without telling them let them sample your mead, wild wine, or beer. They won't taste anything and you'll feel much more confident about it.

PS. One teaspoon of acid blend should do the trick for a five gallon boil to oxidize the aluminum.

It makes no difference at all.. ----------->Denny

I'd like to add to that - aluminum is also not very good at dispersing thermal energy and one can develop a wicked "hot spot" on the bottom of your pot during boiling, which may not be desireable. For even heat distribution, statinless steel is your pot of choice in this context.

-------------------------------------------- John Bleichert - snipped-for-privacy@earthlink.net Have you been eaten by a grue lately?

Really? I was under the impression that aluminum was a far better _conductor_ of heat than stainless -- one of the reasons that it is used extensively in the construction of heat sinks. Wouldn't good conduction characteristics imply good dispersal characteristics, or are these not really the same thing? I'm just asking -- I use Al in brewing, but only for heating water, not as a wort boiler, so I wouldn't notice hot spots.

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Teleoperate a roving mobile robot from the web:

Not exactly. How well a plate of metal disperses heat is a function of both its conductivity and its thickness. A good first-order approximation is that dispersion is proportional to conductivity*thickness.

So, for good dispersion, you need a thin layer of a highly conductive material, or a thick layer of a poorly conductive material. Too thin or too low in conductivity, and you'll get hot spots.

However, you don't want to get the material too thick, since the thicker the material is, the slower its response to a change in the input temperature (this is government by the conductivity and thickness as the metals, as well as the specific heat and density of the metal). So if you make a pot with a honkin' thick bottom to keep good uniformity, it will also be poorly responsive to changes in burner intensity. This is often more dangerous than "hot spots", since it's often hard to precisely regulate burner intensity, so if you are overheating whatever it is your are boiling/cooking, it will take some time for the material to respond to the decrease in input heat, and you'll keep over- and under-shooting the target. This make sense?

Alas, both the problem of hot spots and the problem of poor thermal response are often lumped together.

As to the original topic of comparing SS to aluminum: you can't directly compare them without knowing the thicknesses, and beware of pots that have really thick bottoms as well.

Well, when you use highly technical jargon like "honkin' thick bottom" it DOES tend to muddy the waters a bit, but, yes -- it makes sense.

When brewers talk about using al pots, I think they usually mean the turkey-fry variety -- I have no idea what the thickness is on these (even though I have one). I imagine conductivity also varies with alloy used.

As a practical matter, however, homebrewers use these pretty extensively with no major problems reported. I'm speaking of grain brewers, where full volume boils are the norm. The situation may be somewhat different for extract brewers, where concentrated boils are used and care has to be taken when adding extract to make sure it doesn't settle on the bottom of the pot and scorch. Most extract brewers I know generally use fairly thin SS pots, though, which are pretty cheap in the 3-4 gallon range.

Cheers -- m

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Teleoperate a roving mobile robot from the web:

That's why I got a PhD in mechanical engineering, so I can use such precise terminology.

From my experience, it's usually 3-5 mm, which is pretty close to the ideal thickness for Al, and doesn't provide any major complications when forming the pot.

A bit, but not much. Pure Al is around 30% more conductive than most alloys (as opposed to copper, where even a little bit of alloying metal usually cause's a huge drop in conductivity)

There's no substitute for stirring...

'struth. I haven't brewed much yet (mostly still researching and getting equipment and brewing with friends) but after cooking for years (professionally and personally) I've had better luck avoiding hotspots with stainless steel, *always*.

Luckily I've got a nice big ss stockpot to get started with :-)

-------------------------------------------- John Bleichert - snipped-for-privacy@earthlink.net Have you been eaten by a grue lately?

John Bleichert wrote: [snip]

Hot spots aren't a big deal with all-grain brewing -- typically (again, all grain) you're boiling a large volume of liquid which isn't very dense -- w/ specific gravities typically ranging from 1.030 to 1.085. Primarily, the only issue is a bit of protein that "cooks" on the bottom, but not scorching. Of course, this cooked protein is a lot easier to clean from stainless because of the variety of cleaning agents available -- the reason I use stainless -- but a lot of brewers feel no need to get the pot completely clean beyond what they get with the application of a little elbow grease.

It's really more of a cost issue for most people -- a 10 or 15 gallon Al pot is a hell of a lot cheaper than a 10 or 15 gallon SS pot. 8.5 gallon enameled steel canning pots are another limited but inexpensive option for people starting out.

Enjoy the hobby -- it's addicting.

Cheers -- m

This is probably less to do with thermal conductivity et-all and more to do with surface finish, Aluminum will get pitted and all the nice sticky proteins from beermaking will stick to the surface and burn, as SS remains smoother then it probably does not catch the solids as readily.

Ben. NB the above is only my own personal view.

Not in terms of pasteurizing. It is true that most amateurs will get their grapes in worse shape than a commercial winery will. We will generally give the bunches a good looking over and pick out any moldy grapes. Sulfite additions at crush are recommended for grapes that are a bit "gamey". But for the most part the higher alcohol and lower ph of wine as compared to beer, as well as maintenance of appropriate free SO2 levels, will protect the wine from spoilage.

Brian